1 Answer

You just need to use a move that isn't blocked by wonder guard (Flying/ Fire/ Rock/ Ghost/ Dark), then the substitute will break, then you'll be able to hit Shedinja.

You can also force it out of it with roar/ whirlwind.

Additionally, any weather buffeting or entry hazards will KO Shedinja on switch in.

EDIT: so you're asking if the substitute will break after 1 super-effective attack? Yes it will. Something like Rock Blast (as suggested) will break the substitute on the first hit, then KO Shedinja on the second hit (unless it's holding a sash, in which case it will KO Shedinja on the third hit).

A substitute will take the damage, no matter how high the damage is, and will fade after one hit if the damage is high enough. While it has 1/4 of the HP of the Pokemon that made it, Shedinja's low defences mean that the substitute will break in nearly all cases.

While most everything here is correct, you are wrong in saying that the Substitute holds 25% HP of the pokemon behind it. Substitutes always have 25% HP of the pokemon that set the sub, not the pokemon behind it. So if a pokemon with 400 max HP sets a Sub and Baton Passes it to Shedinja, the Sub would have 100 HP (assuming the sub didnt take any damage before being passed), regardless of how much HP Shedinja has.

Really? I've always determined it to be HP of the Pokemon behind the sub, but maybe that's because it's been hit by a SE move and therefore the sub is broken due to low defences. Lemme change that, thank you.